Microbiology, Science and Society
• The biological science
• The Genetic information.
• Microorganism have as a news source of product and
process for the benefit of society.
Ex alcohol, Insulin, glutamate
Clean up of the environment, decomposition of
petroleum compound in oil spill decomposition of
herbicides and insecticides.
National and International guideline and regulation
Invisible world of bacteria algae fungi protozoa and
Virus.
Cause disease of humans, animal and plants
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Food Processing
1
Germ theory of Fermentation
• Fermentation occurs, and through a series of
biochemical change alcohol and other substances are
produced from grape sugar.
• Ancient culture developed beverages and food we know
are products of microbial fermentation.
Ex. Kiu (Chinese rice beer), Sake (Japanese wine)
produced by the microbial fermentation of a rice mash.
• The soy sauces of China and Japan, derived from
fermented beans, have been made for centuries.
• In the 1850s Pasteur help from the French wine industry
he found microorganism of different kinds from both
good and bad batch of wine.
• Certain types of microbes predominated in the good
testing wine.
Pasteur concluded that
selection
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Facculty of Agriculture
and of microbes could 2
Food Processing
ensure a
Germ Theory of Disease
• Pasture and his assistant were revolutionizing the wine
Industry. They were affirming a new theory of what cause
disease the germ theory of disease.
The germ theory of disease
• In history the disease was cause by such vague factors
as bad air or bad blood.
• Pasteur was asked to investigate a silkworm disease
that threatened to ruin the French silk industry.
6 years later he proving that a type of microorganism
called a protozoan, caused the disease.
In Germany, Robert koch (1843-1910), his career as a
physician.
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• Both Pasteur and Koch discover the cause of anthrax (a
disease decimating the herbs of cattle and sheep in
Europe)
• Koch proved the bacteria cause of anthrax
• 6 years after he first stared into his new microscope.
• Koch prove are kind of microbe cause one definite kind
of disease.
• Koch and his colleague discovered the bacteria that
cause tuberculosis and cholera.
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Food Processing
4
Developments in Disease Prevention
• It is difficult to comprehend the magnitude of human
misery and devastation caused by microbial and viral
disease.
• Plague, typhus diphtheria, small pox, cholera and
influenza devastated vast regions of the world.
• Black death cause by a bacterium, occurred in Europe
during the period 1347-1350.
• One-third to one-half of the French population died from
the disease.
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Deaths cause by influenza
• Antisepsis, prevents the spread of infectious diseases by
inhibiting or destroying the causative agents
• Immunization, a process that stimulates body defense a
gains infection.
• Chemotherapy treating disease with a chemical
substance.
• Improved public health, measures like better sanitation
particularly as related to water and food, reduced the
spread of microorganism and the incidence of disease.
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Food Processing
6
Developments in Non-medical Microbiology
• Results if research on the role of microorganisms in
agriculture and industry
• Russian microbiologist Sergei Winograsky (1856-1953)
say certain soil bacteria could take nitrogen from air and
convert this nitrogen in to a form that can be used as a
nutrient for plan.
• He discovered that certain microbes would grow only on
a mixture of inorganic compounds.
Ex you want to isolate from soil a microbe that has the
ability to decompose cellulose, with is the major carboncontaining substance in plants.
UBB, Facculty of Agriculture and
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• First you would prepare a liquid medium with cellulose
added as the only carbon source and dispense in to
flasks for test tube.
• Then you would inoculate the medium with soil, incubate
it for several day and make a transfer to transfer to fresh
medium.
• Beijerink discovered the bacteria grow in the root tissue
of leguminous plant, such as alfalfa clover and soybean.
• These bacteria capture nitrogen from the atmosphere
and feed it to the plant.
• Today farmers inoculate deeds of legumes prior to
planting with special culture of these bacteria to enhance
crop yield.
• Fermented products such as yogurt. Starter cultures of
microorganisms for the quality of their product.
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Food Processing
8
Microbiology and Biochemistry
• Microorganism to produce chemical change.
• The studies were refined to determine step by step the
pathway for these chemical reactions.
• J.Kluyver observed many of the microbial chemical
reactions also occurred in other organisms including
human, he pursues the theme of unity of biochemistry
among microorganism.
• The concept of unity in the biochemistry of living systems
came from experimental evidence on the notional
requirements of bacteria.
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Food Processing
9
Procaryotic and Eucaryotic call structures
• Morphology of bacteria
measurement in micrometers (m=1/1000nm=10-3mm or
1/25400in)
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Food Processing
10
Developments in Non-medical
Microbiology
• Results of research on the role of microorganisms in
agriculture and industry.
• Russian Microbiologist Sergei Winogradsky (1856-1953)
say certain soil bacteria could take nitrogen from air and
convert this nitrogen into a form that can be used as a
nutrient for plan.
• He discovered that certain microbes would grow only on a
mixture of inorganic compounds.
Ex you want to isolate from soil a microbe that has the ability
to decompose cellulose, with is the major carboncontaining substance in plants.
First you would prepare a liquid medium with cellulose
added as the only carbon source and dispense in to flasks
for as the test tube.
Then you would inoculate the medium with soil, incubate
for several days, and
a Agriculture
transfer
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Facculty of
andto fresh medium.
11
Food Processing
• Beijerinck discovered the bacteria grow in grow
in the root tissue of leguminous plant, such as
alfalfa clover and soybean.
• These bacteria capture nitrogen from the
atmosphere and feed it to the plant.
• Today farmers inoculate seeds of legumes prior
to planting with special culture or these bacteria
to enhance crop yield.
• Today wineries breweries and manufacture of
cheeses, butter and fermented products such as
yogurt. Starter culture of microorganisms for the
quality of their product.
UBB, Facculty of Agriculture and
Food Processing
12
Microbiology and Biochemistry
• Microorganisms to produce chemical change.
• The studies were refined determine step the
pathway for these chemical reactions.
• J. Kluyver observed many if the microbial
chemical reaction also occurred in other
organisms including human.
• He pursued the theme of unity of biochemistry
among microorganism.
• The concept of unity in the biochemistry of living
systems came from experimental evidence on
the nutritional requirements of bacteria.
UBB, Facculty of Agriculture and
Food Processing
13
Procaryotic and Eucaryotic cell
Structures
• Morphology of bacteria
measured in micrometers (m=1/1000mm=103mm=1/25400in)
Bacteria cells vary in size depending on the species.
Ex Staphylococci and streptococci are spherical bacteria
with diameters ranging from 0.75 to 1.25 m
The rapid replication of bacterial is used in experiments to
provide more information more quickly.
Ex the bacterium more Escherichia Coli
undergoes cell division in about 20 minutes while a
mammalian cell in laboratory culture culture takes about
13 to 24 hours to divide into two cell.
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Shape
•
Arrangement
Flagella and Pili
•
•
•
Cell wall: a rigid structure
Properties and Chemical composition of
Bacterial cell wall thinner (10 to 15 nm) gram
negative.
The basic structure contains three kinds
1. NAG N-acetyl glucosamine
2. NAM N-acetyl muramic acid
3. A peptide made of four amino acid or tetra peptide
(some amino acids)
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• Wall of gram-positive Eubacteria : much greater amount
of peptidoglycan
• Wall of Gram-Negative Eubacteria, lipoprotein,
lipopolysaccharides (LPS)
Cytoplasmic Membrane
• As seen by electron microscopy the site of specific
enzyme activity and transport of molecules into and out
of the cell.
• Structure and Chemical Composition of the Cytoplasmic
Membrane
- 20, 30 % primarily of phospholipids
- 50, 70 % proteines
Phospho lipid melecule contains a charged, polar head (the
phosphates end) and an uncharged. Non polar tail (the
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hydrocarbon end) UBB, Facculty of Agriculture and
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Function of the cytoplasmic Membrane
• Some process essential to the cell located in the
cytoplasmic membrane.
• Mesome may lie near the cytoplasmic membrane or
deeper inside the cytoplasm.
Internal Cell Structure
Material contained may be divided into
1- the cytoplasmic area
2- the nuclear material or nucleoid (DNA)
Cytoplasmic area
The cytoplasm is about 80% percent water, along with
nucleic acids, proteins, carbohydrates, lipid, inorganic
ions many law-molecular weight compounds and
particles with various function.
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Nuclear Area
• Call the nucleoid consist of a single, circular
chromosome
• Dormant form of procaryotic Microorganisms
some species of bacteria produce dormant
forms celled spore and cysts that can survive
unfavorable conditions, such as drying or heat.
• Spores
Spore that form with the cell, called endospores
are unique to bacteria
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• Thick-walled, highly re-fractile and highly resistant to
environmental change.
• Endospores contain large a mound of dipicolinic acid
(DPA)
• Conidium (conidia), is not much more heat-resistant than
a vegetative cell.
Cyst
Like endospore, cysts are dormant thick-walled
forms that resist drying.
They develop from a vegetative cell and can later
germinate under suitable conditions.
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Food Processing
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Nutritional Requirement and Microbiological
Media
• Of all living organism microorganisms are the most
versatile and diversified in their nutritional requirements.
• Chemical elements as Nutrients
Cross Morphological Characteristics of
Eucaryotic Microorganism
• All Procaryotic organisms, yet only a few groups of the
Eucaryotic organisms include micro organisms.
• Algae, Fungi, Protozoa
Ex The seaweeds, which are algae, and the mushrooms,
witch are fungi.
UBB, Facculty of Agriculture and
Food Processing
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Morphology of Fungi
• Yeast and Molds are Fungi
• They differ in their morphology
• Single yeast larger than most bacteria, are commonly
oval, elongate or spherical.
• They form smooth, glistening colonies
• The body, or thallus (plural thalli) of a mold consists of
the mycelium (mycelia) and the dormant spore
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Food Processing
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Hyphae (singular, hypha)
• Some hyphae are embedded into solid media such as
bread.
• Reproductive hyphae may grow up ward into the air to
disseminate the spore they produce.
• Pathogenic fungi exhibit dimorphism, either in a
unicellular, yeast like fore or filamentous from
Morphology of Algae
• Algae as a group are potpourri of sizes and shapes.
• Single- celled species may be spherical, rod-shaped,
club-shaped, or spindle-shaped.
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Food Processing
22
Microbiology of the soil and
the atmosphere
The soil environment
• Soil is the region on the earth’s crust where
geology and biology meet, the land surface that
provides a home to plant, animal, and microbial
life.
• If you compare the physical and chemical
characteristic of soil from desert and farmland.
• Soils are characterized by horizons, parallel
layers of various.
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Food Processing
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Enumeration and Isolation of Soil
Microorganisms
•
The techniques that used to estimate the numbers and
kinds of soil microorganism include the agar-plate
culture technique, direct microscopic examination and
the enrichment culture technique.
•
Agar-Plate culture Technique
Dilution of the soil sample, are added to tubes of
melted and cooled agar medium and the contents of
the tubes are poured into Petri dishes.
Ex if you use nutrient agar and incubate the plates at 250C
in an air atmosphere in the dark for 48 hours….
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Food Processing
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You can use the method at you want
1.
2.
3.
4.
You will not be able to detect the following of microbes,
Anaerobes and microaerophile,
Strict thermopiles' and psychrophile,
Photoautotroph, because they require light as an energy source.
Chemoautotroph's, because they proffer inorganic nutrient.
Direct Microscopic Examination
For direct microscopic examination, a dilution of soil sample is spread a
thin film on a glass slide.
Scanning electron microscopy has been used to search for
microorganisms in soil.
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Food Processing
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Enrichment Culture Technique
•
•
The enrichment culture technique does not provide quantitative
information on the microbial flora present in any given sample.
Instead, it helps isolate microorganisms that are able to
metabolize a particular substrate and that may be present in very
small number in the original sample.
Soil Microorganisms
The number and kinds of microorganisms present in soil depend
on many environmental factor.
1.
2.
3.
4.
5.
6.
Amount and type of nutrients available.
Available moisture.
Degree of aeration
Temperature.
PH
Practices and event that may add large numbers of microorganism to
the soil.
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Food Processing
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Bacteria
• Bacteria account for the largest portion of the microbial
population of soil, in both number and variety.
• Most soil bacteria are heterotrophic and spore forming
bacilli are common
Ex Bacillus, Clostidium, Arthrobactor, Pseudomonas,
Rhzobium, Azotobacter and Nitrobacter
Approximate Numbers of Organisms Commonly Founds in Soils
Organism
Estimated numbers/g
Bacteria
3’000’000 to 500’000’000
Fung i( other than yeasts )
5’000 to 900’000
Yeasts
1’000 to 100’000
Algae
1’ooo to 500’000
Protozoa
1’000 to 500’000
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• Cyanobacteria, the oxygen-producing photosynthetic
bacteria play a key role in the transformation of rock to
soil.
Fungi
Hundreds of different species of Fungi in habit the soil
they are most abundant near the soil surface, where
oxygen is readily available.
Ex Penicillium, Mucor, Rhizopus, Fusarium, Cladosporium,
Aspergillus and Trichoderma.
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The physical
• The physical and chemical (nutrient) conditions in soil will dictate the
predominant species.
• Fungi are very active in decomposing the complex organic
constituents of plant tissues such as cellulose, lighting and pectin.
• Yeasts are most likely to occur in the soils of vineyard, orchard, and
apiaries, since they are abundant on the leaves, stems and fruit that
drop onto the soil.
Algae
The algal population of soil is usually smaller than the population of
either bacteria or Fungi
The major kinds of algae present are green algae Chlorophyta and
the diatoms chrysophyta.
In some situation alga can perform important beneficial changes.
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Protozoa and Virus
• The number of protozoa in moist, rich soils ranges from
a few hundred to several hundred thousand per gram.
• Most soil protozoa feed upon bacteria and other organic
material.
• Some soil bacteria contain bacterial Virus (bacteriophages)
UBB, Facculty of Agriculture and
Food Processing
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The Phizospere
• The Rhizosphere is the region where soil ant Plant root
make contact.
• The number of microorganisms on and around roots is
greater than that in root-free-soil, the kinds of
microorganisms in the Rhizosphere also differ from
those in root-free soil.
• The products of microbial metabolism that are released
into the rhizosphere stimulate the growth of the plants.
Interactions among soil microorganisms
Symbiosis is a condition in which the individuals of a
species live in close association with individuals of an
other species.
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Mutualism
• Mutualism is the form of symbiosis in which each
organism benefits.
Ex Lichen are composition microorganism, Lichen and
many other substrates the may be unsuitable for growth
of other organisms.
Ex nitrogen fixing bacteria growing in the roots of legumes.
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Commensalism
• Commensalism is an association in which one organism benefits
and the other is not affected.
For example many fungi can degrade cellulose to glucose and then
bacteria, most of which can not degrade cellulose, can use this
glucose.
Other example of commensation is the is the ability of a
combination of species to attack a particular substrate
when an individual species cannot.
For instance, lignis a major chemical constituent of wood
Is usually resistant to degradation by pure culture of microorganism
under laboratory conditions.
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Food Processing
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Antagonism
• Antagonism is the inhibition of one species of organisms
by another.
Ex Antibiotic production by microorganism
Competition
The fact that soil is inhabited by many different species
of microorganisms suggests that there is likely to be active
competition among some of these species for available
nutrients.
Nutrients
rapidly growing species
=> grow more
slowly of food
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Food Processing
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Parasition
Parasition is an interaction in which one organism lives
in or on the body of another organism.
The parasite is dependent upon the host and lives in
intimate physical contact and metabolic association with
the host.
Predation
Predation is an association in which one organism, the
predator feeds on and digests another organism, the
predator, feeds on and digests another organism, the prey.
Ex Some protozoa feed upon bacteria and some algae called Grazing
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Microbiology of Natural Waters,
Drinking Water, and Wastewater
Natural Water
The hydrologic cycle = the earth’s moisture circulates to
and from the atmosphere.
The passage of water into surface waters and by
Transpiration from plans, and the subsequent precipitation
of moisture in the atmosphere in the form of rain, snow or
Hail fall back to eath.
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In the cycle, natural water can be classified into three
major categories, base on their location:
1. Atmosphere water: water contained in clouds and
precipitated as rain, snow, or hail
2. Surface water: bodies of water such as lakes, steams,
rivers, and oceans.
3. Groundwater, water beneath the surface of the earth
where all pores of soils as well as spaces in and among
rocks are saturated.
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The Aquatic environment
• The kinds of microorganisms found in an aquatic
environment are to a large extents, determined by the
physical and chemical conditions that prevail in that
environment.
Environment condition factors as temperature, light, pH
and nutrients
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Temperature
Temperature of surface water range from OC in
Polar regions to 40 ºC in equatorial regions.
Some hemophilic bacteria have been isolated from
Anaerobic sediments near cracks in the ocean floor.
Ex the archeobacterium Pyrodictium occultum was isolated
From a submarine field near the island of volcano, Italy
where water as hot as 103C.
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Hydrostatic Pressure
• Hydrostatic Pressure is the pressure at the bottom of a
vertical column of water.
Ex It increases with water depth at the rate of 1 atmosphere for pressure (14.7 lb/in2) for every 32.8 ft (10m)
• Barophilic organisms: are organisms that can not grow at
normal atmospheric pressure and require high hydrostatic
pressure.
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Food Processing
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Light
• Most forms of aquatic life depend, directly or indirectly
Upon the metabolic products of photosynthetic organisms.
• The principal photosynthetic organisms in most aquatic
Habitats are algae and cyanobacteria, growth is restricted
to the upper layer of waters through which light can
penetrate.
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Salinity
• The salinity, or sodium chloride concentration, of natural
Water ranges from near zero in fresh water to saturation.
(32 NaCl) in salt lake such as the Great Salt lake in Utah.
Seawater contain approximately 2.75% NaCl.
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Turbidity
•
1.
2.
3.
There is a marked variation in the clarity of surface
water.
The suspended material responsible for water turbidity
includes
Particles of mineral material, which come from coastal
erosion.
Detritus, which is particulate organic matter such as
fragments of cellulose, hemi cellulose, and chitin from
decomposing plant and animal matter
Suspended microorganisms,
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Hydrogen ion concentration ( pH )
Aquatic microorganism usually grow best at pH 6.5 to 8.5
Lakes and River may show a wider range in pH depending
upon local environment conditions.
For example, archaeobacteria have isolated from salt lakes
in Africa where the pH is 11.5.
* Mercury and other heavy metals from industrial wastes
may inhibit the growth of some microorganism.
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Nutrients
The amount and kind 0f organic and inorganic materials
(nutrients) present in an aquatic environment, significantly
Influence microbial growth.
Nitrates and phosphate are common inorganic
Constituents and they promote the growth of algae.
Near-shore water, which receive domestic wastewater
Containing organic and inorganic compounds, are subject
to intermittent variations in their nutrient load.
Industrial wastes
contribute antimicrobial
substances to estuaries and coastal waters.
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Distribution of Microorganisms in the
aquatic environment
Microorganism in the aquatic environment may occur
at all depths ranging from the surface to the very bottom
of ocean trenches.
Freshwater Environments
The microbiology of freshwater environment is a part of
The science of limnology, which is the comprehensive
Study if all organisms living in lakes, ponds, and
streams.
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Lakes and Ponds
1.
2.
3.
4.
Lakes and Ponds have characteristic zones or layer.
The littoral zone: light penetrates to the bottom.
The limnetic zone: is the upper region in open areas a
way from the shore.
The profound zone refers to the deeper regions of the
open water (photosynthetic activity decreases
progressively in this zone).
The benthic zone is the soft mud or ooze at the
bottom.
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Streams and Rivers
• Most of the nutrients in streams and rivers come from
the surrounding terrestrial system.
• The terrestrial condition
the effects of domestic,
agriculture and industrial practices.
• The drastic environment changes in streams and rivers
created by rapidly expanding urbanization and by
changes in the way land is farmed make it impossible to
describe a characteristics microbial population.
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Oceans
• Microorganisms inhabit all depths and all latitudes in
ocean.
Ex part of plankton, marine plankton
The phytoplankton population consists of numerous
specious of cyanobacteries as well as algae (diatoms)
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Marine Fungi and Protozoa
• Marine bacteria and algae, some fungi and protozoa are
found in ocean.
• Fungi (deuteromycetes phycomycetes, and
myxomycetes) have been isolated from marine
environments.
Microbial Deposits
Many of the algae and protozoa that inhabit zone at the
surface have calcium or silica containing cell walls.
Microorganisms also play the major role in formation of
petroleum deposits from accumulated and buries organic
materials.
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The role of aquatic Microorganisms
• Aquatic life includes interactions among microorganisms
And between microorganisms and higher from of life both
plant ant animal.
• Species of microorganisms carry out biochemical
Changes that recycle element and nutrients in the water in
Much the same manner as that described for soil.
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Food Chains and Food Webs in aquatic
Environment
• A Food chain is a system of relation ships among
organisms that produce food organisms that consume food,
and organisms the decompose plant and animal tissues to
nutrients for the synthesis of more food.
Food web: in most environments the feeding relation
ships in fact an inter connected complex resembling an
intermovement
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The Fertility of the ocean
The farm fertility of the ocean is used to express the
capacity of an ocean for production of organic matter,
also called the ocean’s productivity.
Mixing Phenomena
Microbial population in ocean are also affected by the
flow of nutrients cause by currents.
Upwelling water rises from the bottom region + the
surface
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Drinking Water
The drinking water of most communities and
Municipalities comes from surface sources, rivers, steams,
And lake.
Such, natural water supplies, particularly streams and
river are likely to be polluted with domestic, agricultural,
and industrial wastes.
These modern-day factors have added a new dimension
To water reuse, making it necessary to “speed up”
The natural processes of water recycling and ensure a safe
Water supply.
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Pollution
Water can be perfectly clear, odorless, and tasteless and
yet be unsafe to drink.
Contaminants that pollute water are classified into three
categories: chemical, physical and biological.
Our discussion will focus on the biological pollutants,
Namely, microorganism.
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1.
2.
3.
In order to prevent transmission of these pathogens
there must be
Water purification method that provide safe drinking
water.
Treatment facilities for wastwater prior to its disposal or
reuse, and…
Procedures whereby water can be examined to
determine its microbiological quality.
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Water Purification
water that is safe to drink is free of disease- producing
microorganisms and chemical substances harmful to health
and is call portable water
Non-portable water must be purified fore it can be used
for human consumption.
Purification methods very, depending on the source of
water and the a mound of water needed.
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Single-Dwelling Water Supply
• Under ground source wells and spring, provide most of
the water for individual home in rural areas.
• Surface water should not be used for drinking purpose
unless it is first treated (or boiled) to destroy any
pathogenic microorganism since it will likely be polluted.
Municipal Water Supplies
The principal methods used in a municipal waterpurification pant to produce portable water are
sedimentation, filtration, and chlorination.
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Microorganism As Indicators of waters
Quality
1.
2.
3.
Pathogenic microorganism
Pathogens are likely to enter a water supply
sporadically, and since they nit survive for long periods
of time, they could be missed in a sample submitted to
the laboratory.
If they are present in very small number, pathogens
are likely to escape detection by laboratory
procedures.
It takes 24h or longer to obtain results from a routine
laboratory examination for pathogenic microorganisms.
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Indicator Microorganisms
Some of the important characteristics of an indicator organism
are:
1.
It present in polluted water and absent from unpolluted (portable)
water.
2.
It present in water when pathogens are present.
3.
The quantity of indicator organism correlates with the amount of
pollution.
4.
It survives better and longer than the pathogens
5.
It has uniform and stable properties.
6.
It is generally harmless to humans and other animals.
7.
It is present in great numbers than those of pathogen (making
detection relatively easy).
8.
It is easily detected by standard laboratory technique.
Escherichia Coli, Streptococcus faecalis, Clostridium perfringens,
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Escherichia coli and Other Coli form
Bacteria
The coli form bacteria as a group are characterized as Gramnegative non-spore forming facultative rod-shaped bacteria that
Ferment lactose with production of acid and gas within 48H at 35oC
Use biochemical test
1.
Ability to produce indole from tryptophan E. coli does and
Ent. aerogenes does not.
2.
Amount of acidity produced in a special glucose broth medium
and detested by the pH indicator methyl red.
E. coli produces a lower pH,
3.
Ability to produce the compound acetylmethylcarbinol in a
glucose-peptone medium.
4.
Utilization of sodium citrate.
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Bacteriological Examination of water for Potability
Standard Methods for the Examination of Water and
Wastewater (prepared and published jointly by the
American Public Health Association, the American
Water Works Association and the Federation of
Sewage and Industrial Wastes Association ) and also
in publication of the US Environment Protection
Agency.
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1. The sample must be collected in a sterile bottle.
2. The sample must be representative of the supply from
which it is taken
3. Contamination of the sample must be avoided buring
and after sampling.
4. The sample should be tested as promptly as possible
after collection.
5. If there is to be a delay in examination, the sample
should be stored at a temperature between 0 and 10oC
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1.
2.
The routine bacteriological procedures consist of
a standard plate count to determine the number of
bacteria present and…
Tests to reveal the presence or absence or absence of
coli form bacteria
Standard Plate Count
Usually 1.0 and 0.1 ml quantities of the water sample
are plated on an agar medium and incubated for 24H after
Which the colonies are counted.
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Membrane-Filter Technique
The membrane-Filter technique for the bacteriological
examination of water consists of the following step.
1. A sterile filter disk is placed in a filtration unit,
2. A measure volume of water is drawn through this filter
disk, the bacteria are retained or the surface of the
membrane-filter disk,
3. The filter disk is removed and placed upon an
Absorbent pad that has previously been saturated with an
Appropriate culture medium.
4. During incubation, colonies develop on the filter disk
Wherever bacteria were entrapped.
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Wastewater
Wastewater, or sewage, is defined as the used water
supply of a community and consists of :
1. Domestic water borne waste, including human
excrement and wash waters (every thing that goes down
the drains of a home and city and into its sewage system).
2. Industrial water borne wastes such as acids, oils,
Greases and animal and vegetable matter discharged by
factories.
3. Ground, surface, and atmospheric water that enter the
wastewater system.
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1.
2.
3.
There are three kinds of wastewater systems:
Sanitary sewers, which carry domestic and industrial
sewage.
Storm sewers, which are designed to carry off surface
and rain water,
And combined sewers which carry the wastewater
from both sanitary and storm sewers.
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Characteristics of Wastewater
• Wastewaters exhibit a great diversity in physical, chemical and
microbiological characteristic.
- Physical and chemical characteristic of wastewater
- Microbiological characteristics: Fungi, protozoa, algae, bacteria
and virus are present in wastewater.
- Biochemical oxygen Demand.
The biochemical oxygen demand (BOD) is the amount of dissolved
oxygen required by microorganisms for the aerobic degradation of
organic matter present in wastewater.
The BOD is an indication of the amount of the amount of organic \
material in the sewage, the more oxidizable organic material present,
the higher the BOD.
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Wastewater treatment Process
Untreated wastewater cannot be disposed of without
Serious objectionable consequence.
1.
Greater possibility for dissemination of pathogenic
microorganisms.
2.
Increased danger in using natural bodies of water for drinking
supplies.
3.
Contamination of Oysters and others shellfish by the pollution
making them unsafe for human consumption.
4.
Large losses in the waterfowl population because of pollution of
their feeding grounds.
5.
Increased danger in swimming and diminished value of the water
for other recreational purposes.
6.
Depletion of oxygen supply of the water by unstable organic
matter in sewage, killing aquatic life.
7.
Creation of objectionable condition such as offensive odors and
accumulation of debris, thereby decreasing property values and
recreational uses
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Single Dwelling or Single-Unit Structure
• Treatment and disposal of wastewater from individual
Dwelling or other single-unit structure, such as motel or
Shopping centers, can be accomplished by an anaerobic
Digestion or aerobic digestion tank.
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 The septic tank is an anaerobic digestion tank commonly
employed for treatment of a limited amount of wastewater
 Aerobic wastewater treatment systems are also available
commercial for small-unit situation.
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Municipal Facilities
Municipal wastewater treatments plants carry out a
Series of treatment process
1. Primary treatment = physical remove of coarse solid.
a)
b)
c)
2.
Screening remove
Grit chamber
Sedimentation ( primary settling )
Secondary ( biological ) treatment :
a)
b)
c)
d)
Trickling filter
The activated-sludge
Oxidation ponds
Sludge digestion
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3.
Tertiary ( advanced )
a)
b)
c)
d)
Chemical flocculation
Final filtration
Removal or reduction of phosphate and nitrates
Chlorination
Economics of Wastewater treatment
The average cost of treating wastewater in the United
State is measured in cent per thousand gallons.
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Microbiology of Food
Microorganisms are intimately associated with the
availablelity, the abundance, and the quality of food for
human consumption.
`Food items are easily contaminated with microorgaNisms in natural, during handling, and in processing.
If they are allowed to grow, these microorganisms can
change the physical and chemical characteristic of the
Food and may cause spoilage.
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Significance of microorganisms in food
Microorganisms inhabit nearly every niche on earth,
and
Our food supply is no exception.
The quantity and quality of food you eat is effected
by microbes of many kinds.
Some decompose foods causing spoilage.
1.
2.
Their effects both beneficial and detrimental
The numbers and kinds of microorganisms present in
food reflect the quality and safety of that food.
Some may cause food spoilage.
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3.
4.
5.
6.
7.
Some must be kept out, removed, inhibited, or killed to
prevent spoilage of food.
Some can cause food poisoning or foodborne
infections as described in …
Some can produce certain food products by
fermentation.
Some can be produced in large quantities as a food or
feed supplement.
Contaminating microorganisms create special
problems for the food service industry as more “readyto-serve” and “fest-food” products become available.
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Food as a Medium for growth of
Microorganisms,
• Food as a Medium for growth of Microorganisms poses a
Problem that is different from microbial contamination of
Other kinds of materials, the food itself serves as a culture
medium for microorganism.
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Microbiological Examination of foods
• Standards and regulations have been developed to
Ensure that food receive by the consumer is healthful, safe,
and of the quality claimed on the label.
• Some agencies operate at an international level,
agencies of the United Nation such as
 The Food and Agriculture Organization ( FAO )
 The World Health Organization ( WHO )
 The International Children’s Emergency Fund ( UNICEF )
Standard different area, country… work,
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Microscopic Technique
Standard microscopic technique are used for the
examination of some food product.
The Gram stain technique or a methylene blue stain of a
standard fixed smear is normally used for this purpose,
Technique is different depending the place of work.
The breed smear ( count of microorganisms in milk )
The Howard mold-counting slide ( enumerate mold
fragment in food products such as fruits, juices, and
vegetable )
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Culture Techniques
For example, plate culture techniques are used to
Determine a specimen’s total microbial population or count
Some particular group of microorganisms.
Ex
The standard plate count ( SPC ) for counting
bacteria in milk.
Detail more in standard Methods for the Examination of
Dairy Products
Other produce biochemical type of microorganism
The cultivation of virus from food specimens require
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Microorganisms in fresh foods
The inner tissue of healthy plants and animals are free of
Microorganisms and therefore are sterile.
Surfaces of raw vegetables and meats are usually
Contaminated with a variety of microorganisms.
Of property handed and prepared, raw foods should
contain Low numbers of microorganisms.
Various raw food such as meat poultry and egg provide
Different condition for microbial growth and thus differ in
their microbial population.
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Meats
• The carcass of a healthy animal slaughtered for meat
And held in a refrigerate room is likely to have only a low
level of surface microbial contamination.
• The more common types of bacteria occurring on fresh
meats are pseudomonads, staphylococci, micrococci,
enterococci and coliforms.
Poultry
Freshly dressed poultry has a bacterial flora on the
Surface that originates from bacteria normally present on
the live birds and from organisms introduced during killing,
defeathering and evisceration.
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• Bacteria, Yeasts and Molds have been isolated from the
surfaces of processed poultry.
• The bacterial genera Pseudomonas, Acinetobacter,
Escherichia, Flarobacterium and Salmonella.
• The Yeasts Trichoasporom, Torulopsis, Candida and
Rhodotorula
• The molds Penicillium, Alternaria and Aspergillus
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Egg
Some example of bacteria spoilage of eggs are:
Green rots: caused by green-pigment Peudomonas
species that can grow at 0oC
colorless rots: caused by species of Pseudomonas,
Acinetobacter, Alcaligenes and Coliforms.
Black rots: cause by Proteus species which turn
eggs black
Bacteria pf the genus Salmonella have periodically been
a major or problem.
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Fruits and Vegetable
Microbial invasion of plant tissue by bacteria, fungi and
Virus can occur during various stages of fruit and vegetable
development.
1. The more the tissues are invaded the likelihood of
spoilage.
2. Contamination of fruits and vegetable is the type of
postharvest handling use Mechanical handling is likely
to produce break in the tissue.
The pH of fruit = 2.3 for lemon to 5. for banana fungal
growth
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Shellfish and Finfish
Microorganisms found in freshly harvested shellfish and
Finfish reflect the microbial quality of the water from which
They are harvested.
If the water is sewage polluted, the seafood is potentially
Capable of transmitting pathogenic microorganisms.
Ex The marine bacterium Vibrio parahaemoticus
gastroenteriris epidemic in the United States
Shellfish that grow in contaminated water can also
concentrate viruses in their tissues and many be sources
of hepatitis in fection.
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Milk
When milk is drown from the udder of a healthy cow, it
becomes contamination by microorganisms that have
entered the teat canal from the outside.
Source of contamination – milking equipment – the
personnel and the air in the environment.
Milk “Most nearly perfect food”
attention pathogens microorganisms.
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General Principles of Food
Preservation
Methods used to preserved food are based on one or more of the Following principles:
1.
Prevention or removal of contamination
2.
Inhibition of microbial growth and metabolism (microbiostatic action)
3.
And killing of microorganisms (microbial action)
The various practices used for food preservation include:
1.
Aseptic handling and processing
2.
High temperatures
a. Boiling
b. Steam under pressure
c. Pasteurization
d. Sterilization
3.
Low temperature
a.
b.
Refrigeration
Freezing
4.
5.
6.
7.
Dehydration
High osmotic pressure
a. In concentrated sugar
b. With salt brine
Chemical additives
a. Organic acids
b. Substances developed during processing (smoking)
c. Substances contributed by microbial fermentation
(acids)
Radiation
a. Ultraviolet light
b. Ionization radiation.
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Aseptic Handling and Processing
• Each step in preparing a food for
preservation is a potential source of
contamination.
• Use of aseptic techniques is particularly
important in preparing the highly
perishable foods such as fish oysters, and
crabmeat, each of which requires consider
able handling by individuals.
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Aseptic processing is a relatively
new development in the food
industry
• This process uses plastic, paper or/in
containers and the resulting package item
of food offers both economics and user
advantages.
• The product is sterile can be stored at
room temperatures eliminating the need
for refrigeration space.
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High Temperatures
• High temperature is one of the safest and
most reliable methods of food
preservation.
• Knowledge of the heat resistance of
different species of microorganisms,
particularly spore formers, is especially
important in the preservation of food by
high temperatures.
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Canning
• The food places into glass containers, which
were then sealed with corks and reinforced with
wire and sealing wax.
• The most important organism is Clostridium
botulium was the spore forming anaerobe.
• Commercial pasteurization of milk is performed
by one of two methods.
1. LTH = the low-temperature holding method, or
Vat pasteurization
2. HTST = the high temperature short-time
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Sterilization
• Commercial milk-sterilization techniques
have been developed which expose milk
to ultrahigh temperature for vary short
periods of time.
Ex 300 0-F (148.90-C) for 1 or 2 s
Microwave Ovens
The cooking or processing of food using the
microwave oven is dependent upon the
heat generated by microwave radiation.
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Low temperature
• Temperatures approaching 00C and below retard growth
and metabolic activity of microorganism.
Dehydration
Dried foods have been used for centuries, and they are
more common worldwide than frozen foods.
High Osmotic Pressure
Water id withdrawn from microbial cells when
they are placed in solutions containing large amounts of
dissolved substances such as sugar or salt.
Chemical Additives
The addition of chemicals to preserve foods is controlled.
Ex benzoic, sorbic acetic lactic and propionic acid
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Radiation
• The use of radiation is relatively relatively recent
Development in food preservation.
• Ultraviolet light – type of non-ionizing radiation
• Ionizing
Radiation pasteurization
is a tem describing the killings by doses of an ionizing
radiation that are lower than those does required for
sterilization.
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Food Produces by Microorganisms
The microbial fermentation of vegetable, fruits and milk
is used not only to preserve the foods but to give them
Desirable flavors and/or physical characteristics.
Fermented Vegetable
The fermentation of vegetable such as cucumbers,
Cabbage
1. Initiation stage
At first, many of aerobic facultative and anaerobic
microorganisms present on the vegetable begin to grow.
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2.
Primary fermentation stage.
Lactic acid bacteria and fermentative yeast predominate during
this stage.
3.
Secondary fermentation.
Fermentative yeasts
4. Post fermentation stage. Microbial growth, particularly
mold and oxidative yeast my occur on the surface of the
Fermented product.
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Fermented dairy Products
The dairy industry produces a large variety of fermented
Milks as cheese.
Fermented Milks
Fermented foods made from milk, such as sour
Cream and yogurt are mainstays in the human diet.
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Production of cheese
The manufacture of cheese include the following
steps:
1. The curds is separated from the why ( the liquid
portion of curdled milk ).
2. Adjustments are made to the curd, such as adding salt
removing a specific amount of moisture inoculating with a
particular microorganism.
If required and shaping the curb into a desired size
and form.
3. The curb is incubated under condition which favor the
Growth of the desired microorganism.
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Species Racial and Individual Resistance
Resistance to infection varies with the species of animal
or plant.
•
The reason resistance varies from one species to another
is usually unknown.
•
Species resistance is an obstacle in biomedical research.
Ex resistance to malarial infection, may be genetic factor
inherited from their parents.
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External Defense Mechanisms
• External defense mechanisms are another factor in non
specific host resistance.
• Ex be largely mechanical but chemical barriers are also
involved.
Skin and Mucous Membranes
The unbroken skin and mucous membrane are effective
mechanical barriers to infectious agents.
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Chemical Secretions
• Secreted chemical substances with antimicrobial action
are an important component of external defense.
Ex the mucous membranes secrete many substances
including enzymes witch can impair microbial infectivity.
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Foodborn and Waterbone Diseases
• Gastroenteritis and Diarrhea
• Many pathogenic bacteria transmitted by feces
contaminated food or water can cause
gastroenteritis, an acute inflammation of the
gastroinstinal tracts.
Food Poisonings
Food poisoning occurs people consume food
containing a toxin made by a microorganism.
Ex Straphylococcal food poisoning and botulism
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Biology of staphylococcus aureus
• S. aureus cell are Gram-positive cocci grow well under
aerobic and anaerobic condition.
But they do not compete well with other microorganism
present.
S. Aureus produce an enterotoxin
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How Staphylococal Food Poisoning Occurs
•
•
Human carrier are responsible for contamination food
with an enterotoxin producing strain of S. aureus.
Most carriers are not ill and merely harbor the
staphylococci in or on their body usually in the nose,
the hand
1.
2.
3.
4.
The hands of the carrier become contaminated with nasal
secretions.
The carrier’s hands inoculate the food during its preparation.
The food is stored for several hours without being properly
refrigerated. During this period the staphylococci multiply and
produce the enterotoxin.
The food is consume, raw or cooked, raw or cooked.
cooking does not destroy the enterotoxin.
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Botulism
• Botulism is caused by the bacterium Clostriumbotulinum with
produces an exotoxin.
Tree form
Food poisoning botulism, infantbotulism and wound botulism.
Biology of clostridium botulinum
C. Botulinum cell are anaerobic Gram-positive rods. That produce
heat resistant endospores.
Food Poisoning Botulism
The name botulism comes from the latin botulus (sausage). In the
eighteenth century the disease was first associated with the
consumption of sausages.
Botulinum toxin causes paralysis by its action as a nerve poison, or
neurotoxin.
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Foodborne and Waterborne infection caused
by bacteria
• Foodborne and Water borne disease are usually
diseases of the intestinal tract, although other
areas of the body may be affected.
Ex Salmonella gastroenteritis, Typhoid fever,
Salmonella gastroenteritis is caused by bacteria
of the genus Salmonella.
Biology of Salmonella Bacteria
Gram negative facultative rods with peritrichous flagella
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Transmission of Salmonella
• Humans are infected by salmonellas almost
exclusively through the consumption of
contaminated food or water.
• The food sausage, poultry commercially
prepared beef roast and eggs.
• Humans can spread salmonella to other
humans.
• Asymptomatic carrier and ill person may excrete
Salmonellas in their feces, and the Salmonellas
may contaminate their hands.
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•
•
•
•
•
Are involve in food preparation.
Inoculate Salmonella into the food.
Bacteria may multiply to number
Cause in disease in those who eat the food.
The main source of many Salmonella is animal, not
humans.
• Many Salmonella serotype infect chickens turkey ducks
rodent eats dog turtle and other animal.
• Poultry and Poultry products especially raw or
inadequately cooked eggs.
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Foodbrne and Waterbornes
infections case by virus.
• Several viruses cause foodborn and
Waterborne infections.
Ex Rotaviruse and Norwalk viruses infect
only the intestine and cause
gastroenteries.
The hapatitis A virus
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Paralytic Poliomyelitis
Paralytic poliomyelitis is a particularly dreaded disease.
• Biology of Poliovirus
The virus that cause poliomyelitis have an icosahedral
RNA.
• Transmission of Poliovirus
Poliovirus are excreted in the feces of infected humans.
By fecal contamination of hands or food or of water
supplies.
Poliovirus also occur in nose and throat discharges of
patients and can be transmitted by airborne means.
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Pathogenicity of Poliovirus
• Poliovirus multiply initially in the mucors membranes of
the intestine or the pharynx and then penetrate to nearby
lymph nodes and eventually to the bloodstream.
Other Foodborne and Waterborne infection Cause by
virus
Common example of other foodborne and Waterborne
infections caused by virus include diarrhea caused by
rotavirus and the Norwalk group virus and a liver
infection called viral hepatitis type A.
WHO The world Health Organization
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Viral Hepatitis type A
• The hepatitis type A virus (HAV) has an icosahedral
nucleocapsid and contain single-stranded a RNA.
The patient is actively producing serum antibodies again
HAV.
No vaccine is presently available.
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Foodborne and Waterborne infection cause
by protozoa
• Several protozoa cause intestinal illness.
• One of the most important is Entamoeba histolytica,
which causes amoebiasis or amoebic dysentery.
• Amoebiasis (Amoebic dysentery) infected by E.
histolytica
• The infectious form of E. histolytica is non-motile,
dormant from called a cyst.
• The cysts are excreted in the feces of infected
individuals and can be transmitted to uninfected persons
by feces contaminated water or food.
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These large, active amoebas are called
trophozoites
• Ex A single E. histolytica trophozoite can ingest several
red blood cells.
Other Foodborne and Waterborne infection Caused by
Protozoa
Giardiasis caused by lamblia
Balantidiasis cause by Balsntidium coli
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Foodborne and Waterborne infection cause
by Helminths
• Some foodborne and Waterborne infection are caused
by parasite worms or helminths.
Helminths are classified into two main groups
1- the flatworms (the cestodes or tapeworms, the
trematode or flukes)
2- the nematodes or roundworms.
Tapeworm infection (the beef and pork)
tapeworm a longflat ribbon is divided into segments
called proglottids
tapeworm in human? Yes
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• The pork tape worm, Taenia soloum, and beef tapeworm
Tania Saginata.
• Trichinosis
Human usually become infected by eating under cooked
pork and less often horsemeat that contains the cysts
Other intestinal Infection Cause by Helminths
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Pinworm infections
• Pinworm infection of humans are extremely
common worldwide and usually occur in
children.
• The eggs of this worm are carried to the mouth
by fingers contaminated when patients scratch
the anus, which atches intensely when worm are
present in the area.
• Microbiologists diagnose the infection by
detecting eggs trapped on sticky tape that has
been pressed against the anal region. (anus)
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General control measures for prevention of
foodborne and waterborne infections.
•
The are simple, inexpensive measures that should be
practiced by anyone responsible for food preparation
or water supplies
Control of foodborne Infections
1. Inadequately cooked food
2. Improper holding time and temperature for the food
(between preparation and ingestion)
3. Contaminated equipment
4. Poor personal hygiene
5. Inadequate preservation methods
Good personal hygiene is of great impotence in the
control of foodborn diseases
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